The present invention relates to a suspension system which is capable of being adjusted during operation by the operator in response to varying terrains and conditions.
Numerous types of vehicles are used for travel over different surfaces. For example, all-terrain vehicles and snowmobiles may traverse smooth roads, icy paths, deep powder snow, rough terrain then back again to smooth roads, all in a single excursion. The suspension system adjustment for smooth terrain differs from the adjustment for rough terrain. The importance of a properly adjusted suspension system to vehicle performance can be illustrated by snowmobiles.
Quick acceleration and the ability to go through turns with power are some of the most important handling qualities for flat track snowmobile racing. Weight transfer, track tension, spring tension and ski pressure directly affect the handling qualities of the vehicle. Effective weight transfer depends on suspension tension, position of the rider and the position of the front arm 94. Weight transfer in the context of a snowmobile means the shifting of the center of gravity in any direction depending on the force applied. Good weight transfer characteristics are needed for fast acceleration and for cornering. For fast acceleration, it is helpful to shift the weight from the front skis to the snowmobile rear for better traction. For improved cornering, it is helpful to shift the weight forward toward the front skis to hold the snowmobile front end into the turn.
A disadvantage with currently manufactured suspension systems is that a driver is unable to adjust his suspension system while operating the vehicle to match the terrain currently being encountered. For example, in the context of a snowmobile, a driver may move from deep powdered snow onto a long, narrow, icy path up a hill. The driver may need to adjust the snowmobile front or rear suspension systems for proper traction and acceleration up the icy hill and for cornering around the winding path. The driver is not afforded a convenient means for adjusting the snowmobile front or rear suspension systems while driving.
Common methods of adjusting snowmobile suspension require the vehicle to be stopped before any adjustment can begin. Many types of suspension adjustments are inconvenient or impractical when attempted or made in the field.
For example, if trail conditions are ice or hard-packed snow, then a proper suspension adjustment for a snowmobile may be as follows. A rear mounting hole is used to adjust the front arm of the snowmobile rear suspension system. The rear front arm mounting holes are located inside the rear suspension system 70 on the slide rails 98 as shown in FIG. 2. With the front arm mounted in the rear hole, the upper shock absorber eyelet 202 is free-mounted in the lower forward mounting position of the front arm. Then the limiter straps 99 as shown in FIG. 2 are adjusted and secured. Next the front arm eyebolts 92 are adjusted so that there is approximately four inches of clearance between the front arm 94 and the slide rail 98. The suspension system is now set up for riding on hard-packed surfaces or ice.
Later on, if the riding conditions change to loose snow or poor traction conditions which require certain suspension adjustments, the vehicle may have to be stopped again to go through the equally involved procedure for changing the front arm mounting position to the forward hole. Follow the same steps as before in reverse. However, when adjusting the front arm height, adjust the front arm eyebolts 92 to create a standard height gap of 5.5 inches between the front arm 94 and the slide rail 98.
Currently, minor adjustments to the rear suspension system cannot be done on the go and can be slow and inconvenient, especially at night or out in the field.
A further disadvantage to some current suspension systems is with the method for adjusting shock absorber travel. For example, a current method for limiting or enhancing the amount of travel in a shock absorber may involve the use of an eyebolt to adjust the limiter straps. To adjust the front arm eyebolts 92 and limiter straps 99 located in rear suspension system 70, the vehicle must again be stopped. The driver dismounts the snowmobile, the driver lies or kneels down on the ground to reach inside the rear suspension system 70, then turns in the desired direction an eye-bolt locknut with a wrench.
Accordingly, it is the object of the present invention to provide a quick, easy and dynamically adjustable suspension system and method that improves upon or overcomes some of those disadvantages of currently used systems and methods.